The number of structural and configurational isomers of a bromo compound, `C_5H_9Br`, formed by the addition of `HBr` to 2-pentyne respectively, is:

Answer

6

Explanation

Addition of HBr to 2-pentyne gives two structural isomers (I) and (II)
`CH_(3)-C~= CH_(2)CH_(3) overset(HBr)to CH_(3)C(Br) = CHCH_(2)CH_(3) + CH_(3)CH= C(Br)CH_(2)CH_(3)`
Each one of these will exist as a pair of geometrical isomers. Thus, there are two structural and four configurational isomers. Hence, total number of isomers is 6.